There is, in many fields, a need for such an apparatus, for example in industrial applications, in the domestic environment, in the hospital environment, etc. In particular in practical applications in which it must be possible to vary the size of the liquid flow between large and small values, and in which only slight deviations from adjusted temperatures (norm values) are acceptable in the liquid in the flow discharged from the apparatus, extreme demands are placed on the function of the apparatus. Mixers designed for large liquid flows and disposed to discharge, in large flow volumes, liquid within a narrow temperature range are not suitable for use in small liquid flows, since the deviations from preset norm values will, as a rule, be unacceptably large. The same naturally applies if mixers designed to discharge liquid at small liquid flows with slight deviation from the norm value are upgraded in dimensions so as to produce large liquid flows, the mixer for small liquid flows will lose precision in temperature control and discharge liquid at a temperature which often considerably deviates from the norm values. Mixers designed to discharge liquid within a narrow temperature range in both small and large liquid flows are unknown in the art.
Patent specification EP 0 187 484 describes a technique in which computer control is employed to adjust the temperature of a discharged liquid flow to a determined value. The apparatus comprises a multiplicity of valves which are connected pairwise to a supply conduit for hot water and a supply conduit for cold water. From each one of the valves, the water is led to a common supply conduit. A temperature sensor is provided in the supply conduit and feeds back detected temperature to a control unit. Via control devices, the control unit selectively controls the opening and closing of the valves which, in such instance, either assume fully closed position or fully open position. In the use of the apparatus, the temperature of the liquid departing from the apparatus is controlled in that a number of valves connected to the supply conduit for cold water and a number of valves connected to the supply conduit for hot water are opened. In response to the information which the detector feeds back to the control unit, this unit modifies, when necessary, the relationship between the number of open valves for cold and hot water so that the mixture of water which is supplied to the supply conduit will have the correct temperature. In such an apparatus, it is not possible for each individual tapping occasion individually to regulate the flow quantity in those valves which are pairwise connected to supply conduits for cold and hot water, respectively, in order, by such regulation, to achieve a desired temperature during the individual supply occasion of that flow which departs from each pair of valves. The apparatus is primarily intended for relatively large flows, and temperature control is effected by wholly throttling and/or wholly opening the flow in one or more valves which are connected to the supply conduit for cold water and/or the supply conduit for hot water.